Black lock screen problem

[Ashroft98]

It happens when i open google chrome and left it open.Then i lock my phone.But when i press the power button and what i see is only black screen(but the LED is on).The only way to unlock it,is by pressing the power button a little harder.What is actually happening?I already updated my Xperia SP software and google chrome too,but not effect.Helppp,this is my first week using this phone.

[shihstouch]

Try Update Service

Update your phone for optimum performance and get the latest enhancements. Regardless of whether you have the latest software, it’s a good routine to run the Update Service to improve software stability. Also, if you experience problems with your phone this may be solved by a software update.

http://www.sonymobile.com/gb/tools/update-service/

[Ashroft98]

Whats the difference between Sony Update Service and Update Center?

[shihstouch]

Go to the link and you can read more about Update Service